David Harbour and Lily Allen’s daughter Ethel, 8, try out an optical illusion in Croatia

David Harbour jokes around with Lily Allen’s daughter Ethel, 8, as they try out an optical illusion in throwback video from their Croatia trip

He’s recently returned from a sun-soaked getaway in Croatia with girlfriend Lily Allen and her daughters Ethel, eight, and Marnie, seven.

And David Harbour was in good spirits as he took part in an amusing optical illusion trick with Ethel in an Instagram video from the trip, which he shared on Tuesday.

The Stranger Things star, 45, was seen sitting in what appeared to be a large black-and-white chair that made him look small compared to Lily’s eldest child.

Amusing: David Harbour joked around with Lily Allen’s daughter Ethel, 8, as they tried out an optical illusion in a throwback video from their Croatia trip which he shared on Tuesday

Ethel called out to her sister Marnie to ask if she was ‘ready’ and after her sister confirmed that they were she shouted ‘look’ and pointed at the star.

David played along with the illusion as he smiled and waved at the camera whilst sat in the chair, which was actually a cushion placed against the far wall with black bars set down further into the room to make it look like a large chair.

Enjoying the day out, David joked in the caption: ‘(Insert name of Vegas mid-level magician here) EAT YOUR HEART OUT!’ 

Optical illusion: The Stranger Things star, 45, was seen sitting in what appeared to be a large black-and-white chair that made him look small compared to Lily's eldest child

Optical illusion: The Stranger Things star, 45, was seen sitting in what appeared to be a large black-and-white chair that made him look small compared to Lily’s eldest child

Look! Ethel called out to her sister Marnie to ask if she was 'ready' and after her sister confirmed that they were she shouted 'look' and pointed at the star

Amused: David played along with the illusion as he smiled and waved at the camera whilst sat in the chair

Look! Ethel called out to her sister Marnie to ask if she was ‘ready’ and after her sister confirmed that they were she shouted ‘look’ and pointed at the star

Having fun: Enjoying the day out, David joked in the caption: '(Insert name of Vegas mid-level magician here) EAT YOUR HEART OUT!'

Having fun: Enjoying the day out, David joked in the caption: ‘(Insert name of Vegas mid-level magician here) EAT YOUR HEART OUT!’

On Saturday Lily revealed that their fun-filled trip was coming to an end, as she shared a snap of herself and David posing with her adorable daughters Ethel and Marnie off the shores of Split.

As well as uploading a snap the happy group aboard their boat, the Smile singer, 35, also shared a heartwarming clip of her beau dancing with little Marnie.

In the video, the actor was seen holding the youngster in dance pose as he rocked with her to and fro while Bruno Mars’ Uptown Funk played in the background.

Fun in the sun: On Saturday Lily revealed that their fun-filled trip was coming to an end, as she shared a snap of herself and David posing with her adorable daughters

Fun in the sun: On Saturday Lily revealed that their fun-filled trip was coming to an end, as she shared a snap of herself and David posing with her adorable daughters

Wearing a yellow playsuit and red-and-white baseball cap, Marnie stood elevated on a chair on the boat to meet the actor’s height as she gets into the spirit of things.

As her elder sister loudly giggled away in the background, Marnie adjusted her headgear before asking her famous mother if she was filming her.

Also amid the selection of images shared were breathtaking scenery shots from their time sailing the welcoming azure waters off the Adriatic Coast.

Smooth moves: As well as uploading a snap the happy group aboard their boat, the Smile singer, 35, also shared a heartwarming clip of her beau dancing with little Marnie

Smooth moves: As well as uploading a snap the happy group aboard their boat, the Smile singer, 35, also shared a heartwarming clip of her beau dancing with little Marnie

Shaking a leg: In the video, the actor was seen holding the youngster in dance pose as he rocked with her to and fro while Bruno Mars' Uptown Funk played in the background

So sweet: As her elder sister loudly giggled away in the background, Marnie adjusted her headgear before asking her famous mother if she was filming her

Shaking a leg: In the video, the actor was seen holding the youngster in dance pose as he rocked with her to and fro while Bruno Mars’ Uptown Funk played in the background

Captioning the snaps, Lily wrote: ‘Bye bye Croatia. We had the best time, will definitely be back. Special shout outs to our amazing crew on Nostra Vita and @goolets for sorting everything out for us so last minute. Trip of a lifetime for sure.’   

Over the past two weeks, the couple had been seen soaking up the sunshine during their break with Lily’s daughters, who she shares with ex-husband Sam Cooper.

Under new government guidelines, the singer will have to quarantine for 14 days upon her arrival back in the UK due to tightening travel restrictions in COVID-19 hit areas across Europe.

Idyllic: The star branded their holiday the 'trip of a lifetime' as she captioned the set of images

Idyllic: The star branded their holiday the ‘trip of a lifetime’ as she captioned the set of images

Making memories: Lily has spent the past two weeks treating fans to a steady stream of snaps and videos from her sun-soaked family trip

Making memories: Lily has spent the past two weeks treating fans to a steady stream of snaps and videos from her sun-soaked family trip